| 摘要 |
A plurality of mold wall segments are positioned in a circular array in an adjustable fixture to form a mold assembly. The fixture includes a base with a plurality of upstanding pin members. Two of the pin members engage the bottom portion of each mold wall segment. Each pin member is eccentrically mounted on a disc. By rotating the discs relative to their base, the mold wall segments may be moved inward or outward. This movement varies the diameter of the lower portion of the mold assembly. The pin members have threaded end portions which enable the pin members to be moved along their upstanding central axes. This movement varies the height of the lower portion of the mold assembly. In addition, the fixture includes a plurality of radially extending adjusting rods, each rod engages a radially inner side surface of a mold segment. By moving the rods radially inward or outward, each mold wall segment is caused to tilt or rotate about an axis extending through the upper end portions of the pin members which engage the bottom portions of that mold wall segment. This movement varies the diameter of the upper portion of the mold assembly. In one embodiment of the invention, the mold segments of inner and outer annular arrays of mold segments are independently movable relative to each other. |
